Piers Morgan due before the Leveson inquiry today

Piers Morgan, the former editor of the Daily Mirror and News of the World, is to give evidence to the Leveson inquiry into press ethics and standards later today.

Morgan, who now works for TV network CNN in the United States, will appear at the inquiry at London's high court via video link.

His knowledge of phone hacking during his newspaper career has been the subject of serious questions, despite the allegations against the News of the World coming after he left the paper.

Earlier in the month, former News of the World features editor Paul McMullan said that Morgan was the trigger for unethical practices at the now defunct Sunday tabloid, although he stopped short of directly implicating the former editor in the phone hacking affair.

McMullan told the Leveson Inquiry: "My first editor, Piers Morgan, very much set the trend. He was [saying], 'I want that story at all costs. I don't care what you have to do to get that story'. He wanted to be number one, he was driven to sell over 5m copies a week, which is a lot."

Mills did say, however, that the journalist who contacted her was not Morgan, who was editor of the Daily Mirror at the time of the alleged hacking.

Morgan has consistently denied that hacking went on while he was editor of News of the World and The Mirror, and insisted that he has "never hacked a phone, told anyone to hack a phone, or published any stories based on the hacking of a phone".

Also appearing at the inquiry today is former News of the World television editor Sharon Marshall and lawyer Julian Pike.

Yesterday, Stuart Hoare - the brother of former News of the World journalist and phone hacking whistleblower Sean Hoare - told the inquiry that his brother had witnessed daily hacking at the paper, along with routine hacking at The Sun.

Hoare, who died earlier in the year, had previously told the BBC's Panorama program that the then News of the World editor Andy Coulson had ordered him to hack mobile phones.

Coulson, who quit as David Cameron's communications chief earlier in the year, has denied the claims.